Reagent test devices or reagent strips designed to measure analytes, such as glucose, protein, ketone and the like, present in body fluids are well known. Typically, such reagent test devices are constructed to have a reagent pad attached to one end of an elongated substrate which also serves as a handle for the test device. After the reagent pad of the test device has come into contact with a body fluid, such as urine or blood, the colorimetric reaction which occurs in the reagent pad is measured either visually or instrumentally. For visual determinations the reagent pad is normally compared to a standardized color chart. If an instrument is used a beam of light from the instrument is directed onto the reagent pad and the light reflected from the pad is measured.
Typically, a blood sample is applied to the reagent pad of a reagent test device by pricking a finger with a lance or needle and then applying a drop of blood directly to the surface of the reagent pad. Since the reagent pad is normally in an elevated position relative to the substrate of the reagent test device, application of the blood sample can be made with relative ease. However, it is difficult for some individuals to obtain even a small drop of blood to be used as a sample. For this and other reasons there has been a trend toward making the sample application site or reagent area very small. While this means that less sample is required it also means that the application of sample to the sample application site is more difficult.
Diabetics, in particular, tend to have difficulty applying a small blood sample to a small reagent area. One reason for this is the fact that the necessity of repeatedly pricking a finger to obtain a suitable specimen tends to leave diabetics with a loss of feeling or sensitivity in the ends of their fingers and this means that they must rely almost entirely on sight to correctly apply a blood sample to the desired area of a reagent pad. However, another problem faced by diabetics, and particularly with older diabetics, is with the loss of vision or eyesight. Thus, the person required to use the test device may not have good vision.
A further problem which can occur with the use of diagnostic test devices is the fact that the sample applied to a test device does not make good contact with the sample application site. The reason for this is the fact that the person using the test device simple does not place the blood sample at the right location or does not apply sufficient blood sample to adequately cover the area of the reagent pad. Diabetics often have shaky hands either due to age, complications of the disease, or because of low or high sugar levels at the time of providing a blood sample. For such individuals support and guidance of a finger while applying a sample of blood onto a reagent area are highly desirable.
Accordingly, there is a need for means to simplify the positioning of sample onto a reagent test device or test strip without the necessity of making the reagent pad large and without requiring a very large sample. The present invention achieves these goals, eliminating the necessity for large reagent application sites and large sample sizes. In addition, the present invention facilitates the application of sample directly onto the reagent pad in a manner that sample placement and sample volume are eliminated as problems.